This invention relates to a wedge and is more particularly concerned with a wedge for propping open the mouth of a patient (human or animal) in order to facilitate oral examination and/or treatment, eg dental treatment or cleaning of the teeth. Oral examination or treatment on uncooperative patients and especially those with special needs, is usually effected by wedging open the mouth of the patient with a finger or by using a mouth gag or prop, and by restraining head movement. However, there are dangers inherent to this procedure and it is an object of the present invention to provide a dental wedge which can enable oral examination and/or treatment to be carried out more safely both for the patient and for the person carrying out such examination and/or treatment.